The broad goal of this project is to[ integrate developmental and behavioral genetic approaches for alcohol research, by examining ]how genes, individual contexts, and social environments influence alcohol use and misuse directly, and through interactions with each other, and how these relations change over adolescence and young adulthood. The primary aims of this grant proposal are to integrate behavioral genetic and developmental approaches to examine the ways in which predictors of alcohol use, as supported by previous behavioral genetic research, and social ecology and developmental cascade models, relate to alcohol use over age (adolescence and young adulthood) and stage of use (initiation to misuse), as well as how these relations change over time. Specifically, this grant proposes to examine how genes (latent additive effects[/polygenic risk scores]), social environments contexts (parents, peers, and neighborhood contexts), and personal contexts (impulsivity and child maltreatment/abuse) predict alcohol use and misuse over adolescence and young adulthood as direct effects and through interaction with each other.[ Using twin and sibling data, two biometric models (using different approaches, in order to expose the applicant to different ways of twin modeling), will be examined to test a conceptual model of how different social and personal contexts and genes relate to alcohol use directly, and through interaction with each other, a) over adolescence to young adulthood, and b) over initiation, regular use, and misuse of alcohol.] Effects of genes, social environments, and contexts characteristics at specific ages and stages of use will also be examined. Additionally, the effect of specific genes on initiation, regular use, and misuse of alcohol will be examined (directly and through interaction with the previously mentioned covariates) via polygenic risk scores. In other words, this project will examine: (a) if the importance of specific influences change over time (e.g., different ages), (b) if these influences predict changes in alcohol use over time, (c) if the importance of specific influences change over stages of alcohol use (e.g., initiation, misuse), and (d) if these influences predict changes in stage of alcohol use. During the award period, the applicant will be trained in latent growth curve modeling, advanced biometric models (i.e., latent growth curve and multivariate stage biometric models), [and gene-finding techniques such as polygenic risk scores using complete-genome information.] Additionally, she will obtain advanced training in the general science and methodology of alcohol and behavioral genetics research through formal courses, workshops, and didactic meetings with expert consultants. Results from this project will benefit the fields of behavioral genetics and developmental psychology by providing much-needed integration of approaches (a need underscored by experts in both fields). The results will be an important step towards building a more comprehensive and thorough model of how alcohol use develops over adolescence and young adulthood through various underlying mechanisms and external contexts.